Gram positive bacteria: Gram stain is the most

Gram stain is the most important staining procedure in Microbiology. Most bacteria can be broadly classified as Gram-positive or Gram-negative. Gram-positive bacteria stain purple , whereas gram-negative bacteria stain pink. The structural features that define Gram-positive and Gram -negative bacteria are also the very signals that alert the immune system to their presence. Teichoic acids in Gram-positive bacteria and LPS in Gram -negative bacteria are recognized by toll-like receptors—molecular sentinels that trigger inflammation and immune activation. Gram-positive bacterium , any of various types of bacteria that are characterized by having a thick peptidoglycan cell wall and by the absence of an outer membrane composed of lipopolysaccharide. Learn how to identify gram - positive bacteria by their color and shape under a microscope. Find out the common types of gram - positive bacteria and the infections they can cause, such as pneumonia, strep throat, and anthrax.